It is well known to tag petroleum fuels with "silent" markers so that the fuels can be identified for tax purposes, source of manufacture, brand identification and dilution adulteration. Such markers are added to the fuels at low levels, typically at levels of 100 ppm or well below, where they are not readily detectable with the naked eye. However, as it is necessary to be able to easily detect the presence of such markers, a simple chemical test must be available for their detection. A typical petroleum marker reacts readily with a reagent, such as an acid, a base, or in the case of markers described in U.S. Pat. No. 4,209,302, the teachings of which are incorporated herein by reference, with acid and a diazotized reagent, to produce a chemical species which is both extractable in an aqueous medium and becomes highly colored through a chromophoric reaction.
The markers in U.S. Pat. No. 4,209,302 have also found a non-fuel use as markers for asphalt additives, as described in U.S. Pat. No. 5,306,343, the teachings of which are incorporated herein by reference. By use of such a marker, it can be determined whether a contractor is actually adding, and in appropriate amounts, the additive which adds substantial life to the asphalt, but which additive is relatively expensive.
For similar reasons, it would be desirable to tag additives commonly used in waterborne or water-processable materials and compositions. Additives in the form of aqueous solutions, dispersions and emulsions, are often added to concrete to improve its water-resistance, strength and long term durability. Hence, it would be desirable to have a tool or means to ensure that the specific additive is, in fact added to the concrete, in certain high liability end-use applications such as concrete structures of bridges or high-rise buildings.
Likewise, a similar liability exists in the paint industry. It would be desirable to have a simple and economic method for brand/manufacturer identification. Paint companies are known to pay-out large sums of money yearly in order to settle paint failure claims. In many cases, the paint manufacturer has no fool-proof method in identifying that it is its paint that has actually failed. Therefore, claims go uncontested and are settled strictly based on receipts which can be easily falsified.
In fact, there may be rationale for tagging and identifying a wide variety of waterborne products, such as adhesives, coatings, sealants, inks and floor finishes. In general, it is desired that the markers be soluble in non-polar solvents and insoluble in water, particularly at generally neutral pH ranges, so that the markers are not leached out of the tagged materials by exposure to aqueous solutions.
Markers, such as those described in U.S. Pat. Nos. 4,209,302; 5,156,653; 5,205,840; and 5,490,872, the techniques of each of which are incorporated herein by reference, are highly effective markers for petroleum fuels and therefore would be desirable to utilize them in waterborne and water-processable systems. However, as such markers are intended to be compatible with oil, in some cases they also tend to be incompatible with water and aqueous media. The markers of U.S. Pat. No. 4,209,302, for example, are incompatible with water, either by themselves or in the form they are usually sold, as a solution in an oil-miscible solvent, such as xylene, plus a fatty acid, such as oleic acid. If such marker/solvent/fatty acid compositions are added to concrete, they could agglomerate and are therefore unsuitable for tagging purposes.
While oil-miscible markers are suitable for tagging hydrophobic materials, such as petroleum fuels; water-miscible markers are generally unsuitable for admixture with waterborne or aqueous-processable systems for tagging material, such as concrete. Because concrete structures are commonly exposed to the elements, water-miscible markers would leach out over time. Accordingly, it is a general object of the present invention to compatibilize hydrophobic markers, of types currently used to tag petroleum fuels, with waterborne compositions, such as concrete additives.